From: Claudio Sacerdoti Coen <claudio.sacerdoticoen@unibo.it>
Date: Mon, 27 Aug 2012 12:02:53 +0000 (+0000)
Subject: No pattern matching over empty types in Haskell
X-Git-Tag: make_still_working~1547
X-Git-Url: http://matita.cs.unibo.it/gitweb/?p=helm.git;a=commitdiff_plain;h=01dd8b3dcbf02a9645152496d64f649afbbd22b9

No pattern matching over empty types in Haskell
---

diff --git a/matita/components/ng_kernel/nCicExtraction.ml b/matita/components/ng_kernel/nCicExtraction.ml
index 691d8143d..32f5bc35e 100644
--- a/matita/components/ng_kernel/nCicExtraction.ml
+++ b/matita/components/ng_kernel/nCicExtraction.ml
@@ -748,6 +748,9 @@ let rec pretty_print_term status ctxt =
     | LetIn (name,s,t) ->
       "let " ^ name ^ " = " ^ pretty_print_term status ctxt s ^ " in " ^ pretty_print_term status (name@::ctxt) t
     | Match (r,matched,pl) ->
+      if pl = [] then
+       "error \"Case analysis over empty type\""
+      else
       let constructors, leftno =
       let _,leftno,tys,_,n = NCicEnvironment.get_checked_indtys status r in
       let _,_,_,cl  = List.nth tys n in